If you’ve ever had bed bugs, you’ve probably tried everything to get rid of them, including setting off a bug bomb. But a new study shows that these popular consumer products are no match for the blood-sucking pests.

Researchers from the Department of Entomology at Ohio State University looked at three brands of bug bombs, also known as foggers, from a nationwide retailer and tested their effectiveness on five different bed bug populations in the lab.

What they found was what pest-control experts had long thought. “There has always been this perception and feedback from the pest-management industry that over-the-counter foggers are not effective against bed bugs and might make matters worse,” said lead author Susan Jones, an urban entomologist with the Ohio Agricultural Research and Development Center, in a statement. “But up until now there has been no published data regarding the efficacy of foggers against bed bugs.”

Jones and her colleague Joshua Bryant found that Hotshot Bedbug and Flea Fogger, Spectracide Bug Stop Indoor Fogger, and Eliminator Indoor Fogger had little to no effect on the bed bugs. (Only Hotshot Bedbug is specifically labeled for use against bed bugs.) “All three total-release foggers claim ‘kills on contact’ yet all field-collected bed bugs were unaffected upon re-entry,” the authors write. Even five to seven days after contact, the bed bugs remained unharmed.

Since bed bugs spend their time hidden under sheets, mattresses and deep inside carpets, the authors say it is likely they are protected from the foggers’ mist. “These foggers don’t penetrate in cracks and crevices where most bed bugs are hiding, so most of them will survive,” said Jones in the statement.

Even when the bugs do come into contact with the insecticides, their varying levels of resistance to the insecticide and the foggers’ poor toxicity leave the crawlers unscathed. “If you use these products, you will not get the infestation under control, you will waste your money, and you will delay effective treatment of your infestation,” said Jones.

The majority of foggers contain insecticides pyrethrin and pyrethroid. The authors note that most field-collected bed bugs are now resistant to pyrethroids, fueled largely by the unnecessary introduction of insecticides into the environment by humans, according to the researchers. Such resistance has helped drive the resurgence of bed bugs in recent years.

To figure out if your home is infested with bed bugs, here are the (unpleasant) signs to look for, according to the Centers for Disease Control and Prevention:

The bed bugs’ exoskeletons after molting

Bed bugs in the folds of mattresses and sheets

Blood-filled fecal material, which shows up as rusty-colored blood spots, that bed bugs excrete on the mattress or nearby furniture